Allow to customize the SQL search query with Closure

[tortuetorche]

Notice: This pull request is a refactoring of my initial pull request https://github.com/pmatseykanets/laravel-scout-postgres/pull/18 With the help of a Closure, which is more elegant than my previous attempt 😸

Use case:

App\Order::getModel()->searchableUsing()->extendQuery(function ($query, $bindings) {
    // You can customize the SQL query here:
    return $query->addSelect('name');
});
$orders = App\Order::search('Star Trek')->raw();

[tortuetorche]

@pmatseykanets Can you comment or review this pull request, please?

[pmatseykanets]

@tortuetorche With #20 it can be done in the builder callback here, but I'm hesitant rushing into doing so. One of the reasons there is no obvious ordering for $bindings. Depending on what you're doing with the $query in the callback you may need to prepend, append or completely reorder binding values.

[tortuetorche]

Agreed, the binding values need to be manipulating with precautions. But I think, it's the responsibility of the developer to handle correctly the $bindings variable. And this feature is only for advance usages, e.g. using faceted search.

So to handles correctly binding we can do this:

App\User::getModel()->searchableUsing()->extendQuery(function ($query, $bindings) {
    return $query->addSelect('name')
      ->where('organization_name', $bindings->push('GitHub'))
      ->whereIn('role', [$bindings->push('admin'), $bindings->push('moderator')])
      ->where('gender', $bindings->push('male'))
      ->where('active', $bindings->push(true))
      ->whereYear('created_at', '>', $bindings->push(date('Y') - 2));
});
$users= App\User::search('Peter')->raw();

[tortuetorche]

Or more simplier:

App\User::getModel()->searchableUsing()->extendQuery(function ($query, $bindings) {
    $query->addSelect('name')
      ->where('organization_name', 'GitHub')
      ->whereIn('role', ['admin', 'moderator'])
      ->where('gender', 'male')
      ->where('active', true)
      ->whereYear('created_at', '>', date('Y') - 2);

    // NOTICE: The code below could be moved to: https://github.com/tortuetorche/laravel-scout-postgres/blob/23ec3e43429dcbbd58762031e9d5de5ab8f3200f/src/PostgresEngine.php#L289
    // and the $bindings variable could be removed from this Closure
    foreach ($query->getBindings() as $binding) {
        $bindings->push($binding);
     }

    return $query;
});
$users= App\User::search('Peter')->raw();

[tortuetorche]

Closing in favor of https://github.com/pmatseykanets/laravel-scout-postgres/pull/21